Absorbent structures have been developed or proposed for use in absorbent products, such as diapers and sanitary napkins. Such structures typically include multiple layers of materials such as a moisture-pervious facing material, an absorbing material, a wicking or fluid-distributing material, and a moisture-impervious backing material.
When various layers are placed together in face-to-face relationship in such structures, means must be provided for maintaining a desired relationship and for maintaining the structural integrity of the product. In some prior art structures that have been developed or proposed, the outermost or exterior layer on one side of the structure is provided with lateral extensions which are attached by glueing or heat sealing to lateral extensions of the outermost or exterior layer on the other side of the product. The internal layers are thus contained within this envelope formed by the two exterior layers. However, when such structures are used, the internal layers may tend to move and bunch up. Manipulations of the structure during normal use may tend to cause relative displacement or distortions between some of the layers.
To some extent, the undesired relative displacement or bunching of the layers can be reduced by glueing an exterior layer to an adjacent inner layer. However, this necessarily results in an additional manufacturing step. It also requires materials and layer designs which accommodate such glueing, and it does not necessarily reduce displacement between the interior layers.
Accordingly, it would be desirable to provide a structure having a unitary construction that eliminates or substantially reduces bunching or relative displacement between layers.
It would be beneficial to provide a multi-layer absorbent structure which could be fabricated as a unitary, and easily handled, component for use in a variety of products, including disposable diapers and sanitary napkins.
It would also be desirable to provide a unitary absorbent structure having multiple layers wherein intimate contact between the layers is established.
Additionally, it would be advantageous if such an improved absorbent structure could be provided with a moisture-impervious barrier sheet that could be attached to the structure in a way so as to eliminate glueing.